If you insist on sticking with SVN, consider getting yourself an assembla account, which is free with unlimited private and public repos for up to 5 users (but you only get 1GB of storage on the free tier, and it goes up to $24/mo. for up to 12 users/5GB storage). In addition to hosting your SVN, you also get features for issue and bug tracking, project planning, etc.
Google drive and other such file storage can work, but you have to understand that its a separate system -- If you do a commit on your machine to your SVN repository, it may take some time before GDrive and similar catch up, and similarly, other machines have to sync to GDrive before they can sync to the latest changes in the SVN repository.
If you're open to switching to Git, a lot more options become available to you. Nearly all of the free software world has switched from centralized versioning systems like SVN and its predecessor CVS to distributed versioning systems like Git or Mercurial. These models work very differently -- centralized systems work like a library of code files which users check out to change, modify, and then check back in -- distrubuted systems don't operate on checkout/checkin, instead they allow everyone to work in their own branches at the same time, and then merge them in later (with sophisticated tools to automate as much of this process as can be automated). Even for solo developers, many prefer Git or Mercurial over a centralized system -- the different workflow does take getting used to if you come from a centralized version control system, but there's an excellent free ebook that you can browse online or download, or even buy a copy on paper.
For Git, the obvious choice is Github -- creating an account is free, with unlimited free public repositories (e.g. open-source of some ilk). The personal plan is $7/mo and gives a single account unlimited private repositories (you can grant access and accept pull requests from other github users, but you can't give them permissions to push changes directly). If you want additional people to have push permissions, you need to create an organization which is $25/mo for up to 5 users (push permissions) and $9/mo for each additional user -- you get multi-user, multi-role access permissions to control which users have what kind of access on a per-repository basis. You get 1GB/mo free storage and transfer for 'large files' using Git-LFS (things like working files for art assets, you don't want to check those into Git in the usual way), and its $5/mo for each additional 50GB storage/transfer.
Github is the largest and most-active developer community, especially for open source. Its very well developed, very well understood, and full of smart developers. Their pricing structure is pretty sane and fair now, but there's a minor issue if you use Git-LFS that basically means you don't want to use it for open-source projects (It can't be forked by other users, which is the usual workflow for Github). Other than that issue, its got the best tooling and community for hosted source control, hands down.
There's a competitor, GitLab that offers entirely free and as far as I know unfettered Git hosting, and they more or less emulate GitHub with some of their own ideas and changes thrown in. They're entirely free if you use their online system, unlimited public and private repositories, free Git-LFS (IIRC) with no storage or bandwidth limits. Their business model is supported by their on-premises enterprise deployments -- the (minor) downside of that is that if your team scales up such that you need something more than their online experience, you need to migrate to another provider or buy into their enterprise package, which has a minimum seat requirement that makes for high costs -- then again, if you need that level of capability, then your organization can surely afford it.
